Levelling spacer device

ABSTRACT

A levelling spacer device ( 10 ) for the laying of slab-like products (P) for coating surfaces, comprising:
         at least one base ( 20 ) having a lower surface ( 21 ) and an opposite upper surface ( 22 );   a spacer bridge ( 30 ) perimetrically delimiting a through opening ( 40 ) adapted to be crossed by a pressure wedge ( 50 ) along a crossing direction (C), wherein the bridge ( 30 ) is provided with:
           two legs ( 31 ) mutually placed side by side along a flanking direction (D) orthogonal to the crossing direction (C) and each protruding from a respective portion of the upper base ( 20 ) surface ( 22 ), in an orthogonal direction with respect thereto; and   a crosspiece ( 32 ), which joins the top of the two legs ( 31 ) along the flanking direction (D);
 
each leg ( 31 ) of the bridge ( 30 ) being frangibly connected to the respective base portion by means of a respective predetermined fracture line ( 310 ), wherein the fracture line ( 310 ) comprises:
   
           a longitudinal cut ( 3100 ) developing for a predetermined section of the width of the respective leg ( 31 ) with a longitudinal axis (A) parallel to the flanking direction (D); and   at least one trigger element ( 3101 ) of the fracture localized in a predetermined trigger zone of the longitudinal cut ( 3100 ) along the longitudinal axis thereof (A).

TECHNICAL FIELD

The present invention relates to a levelling spacer device for the laying of slab-like products, such as tiles, slabs of natural stone or the like, for coating surfaces, such as walkable surfaces, floors, wall o ceiling coatings or the like.

PRIOR ART

In the sector of tile laying for coating surfaces, such as floors, walls and the like, the use of spacer devices is known which, in addition to equally spacing the tiles placed side by side, allow their planar arrangement, such devices are commonly called levelling spacer devices.

The levelling spacer devices of the known type generally comprise a base, which can be positioned below the laying surface of at least two adjacent tiles, from which at least a spacer bridge protrudes, adapted to contact, by means of its lateral sidewalls, the facing sidewalls of the two tiles to be placed side by side on the laying surface.

The levelling spacer device is then provided with a pressure wedge adapted to wedge between a crosspiece of the spacer bridge and the surface, in view, of the tiles resting on the base, so as to press the visible surfaces of the tiles towards the base, levelling them.

The bridge is then removed by separation from the base following the solidification of the tile laying adhesive, leaving, for single-use, the base underneath the tile laying surface incorporated in the solidified adhesive.

A need felt in these levelling spacer devices, especially in those having bridges of reduced thickness, for example of about 1 mm, and which therefore allow to significantly reduce the distance between two adjacent tiles, is the fact that this bridge is not ripped off at the time of insertion of the pressure wedge, i.e. that the bridge has a high tensile strength, allowing, at the same time, to decrease the resistance to bending or shearing, i.e. to allow an effective and comfortable removal of the bridge following the solidification of the adhesive for the laying of the tiles.

In general, a need felt in these levelling spacer devices is to make the separation of the bridge from the base more and more effective and simple once the adhesive has hardened while maintaining, however, a good tensile strength of the bridge itself that is useful for effectively exercising, by means of the pressure wedge, a pressure on the tiles to be levelled.

Furthermore, a need felt in such levelling spacer devices is to guide the fracture of the bridge from the base as much as possible along pre-established and non-random cutting lines, limiting as much as possible that the separation line runs along random and uncontrolled paths, and—therefore—to avoid that unremoved portions of the bridge remain trapped in the joint lines between the tiles.

An object of the present invention is to solve the aforementioned need of the prior art, within the context of a simple and rational solution and at a contained cost.

Such purposes are accomplished by the characteristics of the invention given in the independent claim. The dependent claims outline preferred and/or particularly advantageous aspects of the invention.

DISCLOSURE OF THE INVENTION

The invention, in particular, provides a levelling spacer device for the laying of slab-like products for coating surfaces, comprising:

-   -   at least one base having a lower surface and an opposite upper         surface defining a bearing plane for two tiles placed side by         side;     -   a spacer bridge perimetrically delimiting a through opening         adapted to be crossed by a pressure wedge along a crossing         direction, wherein the bridge is provided with:         -   two legs mutually placed side by side along a flanking             direction orthogonal to the crossing direction and each             protruding from a respective portion of the upper base             surface, in an orthogonal direction with respect thereto;             and         -   a crosspiece, which joins the top of the two legs along the             flanking direction;             each leg of the bridge being frangibly connected to the             respective base portion by means of a respective             predetermined fracture line, wherein the fracture line             comprises:     -   a longitudinal cut developing for a predetermined section of the         width of the respective leg, preferably for the entire length of         the respective leg, with a longitudinal axis parallel to the         flanking direction; and     -   at least one trigger element of the fracture localized in a         predetermined trigger zone of the longitudinal cut along the         longitudinal axis thereof.

Thanks to this solution, it is possible to define an element localized along the width of the leg with greater fragility, such as to be able to profitably and efficiently trigger the fracture of the leg and its propagation along the line defined by the longitudinal cut.

Furthermore, thanks to this solution, a good compromise is reached between the high tensile strength of each leg, i.e. its function as a traction element of the base under the effect of the thrust of the pressure wedge, and the good bending frangibility and/or cut of each leg itself, which allows the effective removal of the bridge once the tiles are firmly in place.

Advantageously, the trigger element can be localized close to at least one axial end of the longitudinal cut, preferably at a predetermined non-zero distance from this axial end proximal to the trigger element.

Non-zero distance means, in particular, that the trigger element does not incise or coincide with any of the axial ends of the longitudinal cut (to which it is proximal), or, in other words, the external periphery of the trigger element (proximal to the axial end of the longitudinal cut to which it is closest) is detached and not in contact with the aforesaid proximal axial end of the longitudinal cut, or—again—the trigger element (i.e. the outline periphery thereof) is located in an intermediate zone of the longitudinal cut (interposed between the opposite axial ends of the same) at a non-zero distance from each axial end of the longitudinal cut itself, i.e. it divides the longitudinal cut into two portions, of which a first portion interposed between the trigger element and a first axial end (proximal to the trigger element) and a second portion interposed between the trigger element and a second opposite axial end (distal from the same trigger element) and/or another trigger element (where provided).

Thanks to this solution it is possible to define a trigger zone of the fracture close to a longitudinal end of the start of the cut line, thus allowing to define an effective starting point for the fracture.

Advantageously, the trigger element can be a through hole in the thickness of the respective leg with a through axis transverse with respect to the longitudinal axis of the longitudinal cut (i.e. parallel to the aforesaid crossing direction) and which incises the longitudinal cut in the predetermined trigger zone.

Thanks to this solution, the trigger element can be easily realized and is economic.

For example, the through hole has a transverse section, i.e. transverse to the through axis and closed section (i.e. surrounded by a closed perimeter, for example circular or polygonal or of any perimetrally closed shape.

Furthermore, preferably, the closed perimeter is totally contained in the respective leg (i.e. it is defined by a perimeter edge or by a surface of the leg itself).

Alternatively or in addition, the trigger element may comprise a transverse cut which incises the longitudinal cut in the predetermined trigger zone.

Thanks to this solution, the trigger element can be such as to weaken even less the cutting section given by the longitudinal cut.

According to an aspect of the invention, the trigger element defines the trigger zone of the longitudinal cut having a minimum thickness of the entire leg smaller than the minimum section of the longitudinal cut outside the trigger zone.

Therefore, the trigger element defines the weakest zone of the entire leg, from which the fracture of the same preferentially departs.

Preferably, the longitudinal cut can be placed at a predetermined distance from the lower surface of the base, which is such as to be arranged below the level of a surface, in view, of the tiles resting on the base with a support surface thereof opposite to the surface in view thereof.

Preferably, the predetermined distance of the longitudinal cut from the lower surface of the base can be smaller than a distance between the upper surface and the lower surface of the base.

Thanks to this, being the fracture line placed below the surface, in view (preferably below the bearing plane) of the tiles, no part of the base, once the bridge is removed, is above the surface, in view, of the tiles, and preferably not even in the interspace (joint) between the tiles.

According to a further aspect of the invention, the fracture line can comprise a pair of trigger elements separated from each other along the longitudinal axis of the longitudinal cut.

Preferably, each trigger element of the pair of trigger elements can be placed close to a respective axial end of the longitudinal cut, preferably at a predetermined non-zero distance from said respective axial end to which it is close.

Thanks to this, the fracture can be effectively guided, from the beginning to the end, along the longitudinal axis of the longitudinal cut, for example by keeping it bound thereto and, therefore, allowing an effective removal of each leg of the bridge without burrs or remnants of irregular portions that remain attached to the base.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will be more apparent after reading the following description provided by way of non-limiting example, with the aid of the accompanying drawings.

FIG. 1 is an axonometric view of a first embodiment of a levelling spacer device according to the invention.

FIG. 2 shows a front view of FIG. 1.

FIG. 3 shows a side view of FIG. 1.

FIG. 4 is a plan view from above of FIG. 1.

FIG. 5A is an enlargement of the detail A of FIG. 2 according to a first embodiment.

FIG. 5B is an enlargement of the detail A of FIG. 2 according to a second embodiment.

FIG. 5C is an enlargement of the detail A of FIG. 2 according to a third embodiment.

FIG. 6 is a sectional view along the trace of section B-B of FIG. 5A.

FIG. 7 is an axonometric view of a second embodiment of a levelling spacer device, according to the invention.

FIG. 8 shows a front view of FIG. 7.

FIG. 9 shows a side view of FIG. 7.

FIG. 10 is a plan view from above of FIG. 7.

FIG. 11A is an enlargement of the detail C of FIG. 8 according to a first embodiment.

FIG. 11B is an enlargement of the detail C of FIG. 8 according to a second embodiment.

FIG. 11C is an enlargement of the detail C of FIG. 8 according to a third embodiment.

FIG. 12 is a sectional view along the trace of section D-D of FIG. 11A.

FIG. 13 is an axonometric view of a third embodiment of a levelling spacer device, according to the invention.

FIG. 14 shows a front view of FIG. 13.

FIG. 15 shows a side view of FIG. 13.

FIG. 16 is a plan view from above of FIG. 13.

FIG. 17A is an enlargement of the detail E of FIG. 14 according to a first embodiment.

FIG. 17B is an enlargement of the detail E of FIG. 14 according to a second embodiment.

FIG. 17C is an enlargement of the detail E of FIG. 14 according to a third embodiment.

FIG. 18 is a sectional view along the trace of section F-F of FIG. 17A.

FIG. 19 is an axonometric view of a fourth embodiment of a levelling spacer device, according to the invention.

FIG. 20 shows a front view of FIG. 19.

FIG. 21 shows a side view of FIG. 19.

FIG. 22 is a plan view from above of FIG. 19.

FIG. 23A is an enlargement of the detail G of FIG. 20 according to a first embodiment.

FIG. 23B is an enlargement of the detail G of FIG. 20 according to a second embodiment.

FIG. 24 is a sectional view along the trace of section H-H of FIG. 23A.

FIG. 25 is an axonometric view of a fifth embodiment of a levelling spacer device, according to the invention.

FIG. 26 shows a front view of FIG. 25.

FIG. 27 shows a side view of FIG. 25.

FIG. 28 is a plan view from above of FIG. 25.

FIG. 29A is an enlargement of the detail I of FIG. 26 according to a first embodiment.

FIG. 29B is an enlargement of the detail I of FIG. 26 according to a second embodiment.

FIG. 29C is an enlargement of the detail I of FIG. 26 according to a third embodiment.

FIG. 30 is a sectional view along the trace of section L-L of FIG. 29A.

FIG. 31 is an axonometric view of a pressure wedge of a levelling spacer device, according to the invention.

FIG. 32 is a side view of a levelling spacer device in operating configuration.

FIG. 33a is a schematic plan view of a first possible tile laying scheme, so-called “straight”.

FIG. 33b is a schematic plan view of a second possible tile laying scheme, so-called “staggered”.

FIG. 33c is a schematic plan view of a third possible tile laying scheme, so-called “complex”.

BEST MODE OF THE INVENTION

With particular reference to these figures, the reference number 10 generally designates a levelling spacer device adapted to facilitate the laying of slab-like products, such as tiles and the like, generally indicated with letter P, and adapted for coating surfaces, i.e. flooring, walls, ceilings and the like.

The device 10 comprises a base 20, which is, for example, plate-shaped with an enlarged shape, for example polygonal.

The base 20, in the example shown, is a monolithic body which has an irregular (plan) shape, for example substantially octagonal.

The base 20 comprises a lower surface 21, for example substantially flat or “V”-shaped or other shape.

The lower surface 21 is adapted to rest on a layer of adhesive arranged on the screed which is intended to be covered by the tiles P.

The base 20 also comprises an upper surface indicated as a whole with number 22.

The upper surface 22 can be substantially flat or variously shaped according to the needs.

In the illustrated examples, the upper surface 22 comprises a raised first portion 220 (central in the example) defining a bearing plane for two tiles P placed side by side.

The bearing plane, i.e. the highest flat surface of the upper surface 22 which defines the first portion 220, is placed at a first distance d1 from the lower surface 21.

The bearing plane (i.e. the first portion 220 of the upper surface 22) is the surface of the base 20 that is more distant from the lower surface 21.

In practice, the maximum thickness of the base 20 is defined by the first distance d1.

The bearing plane is substantially parallel to the lower (planar) surface 21.

The upper surface 22 of the base 20 furthermore comprises two second portions 222 (lateral in the example) mutually opposite with respect to the first portion 220, for example symmetrical (and equal) with respect to a median plane M of the base 20 orthogonal to the bearing plane and intersecting the first portion 220 and the second portions 222.

Each second portion 222 defines a planar surface placed at a second distance d2 from the lower surface 21, wherein for example the second distance d2 is less than the first distance d1.

In practice, the thickness of each second portion 222 of the base 20 is defined by the second distance d2 and is less than the thickness of the first portion 220 of the base itself.

It is not excluded, however, that at worst the second distance d2 may be equal to the first distance d1.

Each lateral surface is a plane substantially parallel to the lower (planar) surface 21 and to the bearing plane (the two being distinct).

The upper surface 22 comprises a connecting surface interposed between each planar surface and the bearing plane.

The connecting surface is substantially orthogonal to the planar surface and to the bearing plane, defining the elevation of a step between them.

Each second portion 222 of the upper surface 22, i.e. each planar surface, has a longitudinal development, i.e. has a prevalent development direction, along a longitudinal axis A, which is orthogonal to the median plane M of the base 20 which intersects the first portion 220 and the second portions 222.

In practice, each planar surface defines an elongated strip (having a length greater than the width) with longitudinal axis orthogonal to the aforesaid median plane M of the base 20 and placed at a lower level than the level defined by the bearing plane defined by the first portion 220 of the base 20.

The planar surface has a substantially trapezoidal plan shape, for example of an isosceles trapezoid, wherein the larger base is near the bearing plane, i.e. is joined thereto by means of the connecting surface, and the smaller base, opposite it, defines the lateral (free) end distal from the first portion 220 of the base 20.

The upper surface 22 of the base 20 comprises a pair of inclined surfaces 225 opposite with respect to the median plane M of the base 20 which intersects the first portion 220 and the second portions 222.

Each inclined surface 225 defines a protruding ramp from the end of the base 20 towards the aforesaid median plane M in a direction that is orthogonal to the median plane M and which connects the lower surface 21 of the base 20 to the bearing plane of the first portion 220 of the base 20.

Each inclined surface 225 has a maximum distance from the lower surface 21 equal to the first distance d1 and a minimum distance from the lower surface 21 comprised between zero and the second distance d2, preferably equal to the second distance d2.

Each inclined surface 225 lies on an inclined plane of an acute (internal) angle with respect to the lower surface 21.

The base 20 comprises a pair of opposite slots 23 passing from the lower surface 21 to the upper surface 22, which are located at the first portion 220 of the upper surface 22

Each slot 23 has an elongated shape, i.e. it has a prevalent development direction, along a longitudinal axis orthogonal to the median plane M of the base 20 which intersects the first portion 220 and the second portions 222.

In practice, each slot 23 has a longitudinal axis parallel to the longitudinal axis of the second portions 222 of the upper surface 22 of the base 20.

Each slot 23 is open laterally at a respective end of the base 20 distal from the median plane M.

Each slot 23 defines a longitudinal through gap of the base 20 from the end that is distal from the median plane M towards it and with a prevalent direction orthogonal thereto.

The length of each slot 23 is less than half the length of the base 20 in the direction orthogonal to the median plane M, for example it is comprised between 0.4 times and 0.55 times half of the length of the base 20 in the direction orthogonal to the median plane M, for example 0.54 times half the length of the base 20 in the direction orthogonal to the median plane M.

For example, each slot 23 is adapted to intersect a respective inclined surface 225 dividing this into two separate portions along a direction parallel to the median plane M and to the lower surface 21.

The base 20, in particular the upper surface 22 thereof (except for the inclined surfaces 225), has a surface roughness substantially comprised between 20VDI-30VDI.

The device 10 comprises a spacer bridge 30 which, in use, is adapted to contact at least one portion of the facing sidewalls of the at least two tiles P resting on the bearing plane of the upper surface 22 of the base 20.

The bridge 30 comprises two legs 31 protruding from the base 20, for example, each leg is protruding from a respective second portion 222 of the upper surface 22 of the base 20 in an orthogonal direction with respect to at least the first portion 220 of the upper surface 22 of the base itself.

The legs 31 are placed side by side along a parallel (and lying) flanking direction D on the median plane M of the base 20 and mutually spaced apart.

The bridge 30 then comprises a crosspiece 32 which joins the top of the two legs 31 and is arranged with a longitudinal axis parallel to the flanking direction D and parallel and at a distance from the upper surface 22 of the base 20.

The bridge 30 is for example made as a single body with the base 20, for example by injection molding of plastic material.

The bridge 30 is defined globally by a plate-shaped body arranged parallel to the median plane M of the base 20, so that the median plane M of the base 20 is also a median plane of the bridge 30 itself.

Each leg 31 of the bridge 30 has a lower end fixed to the planar surface of the respective second portion 222.

Each leg 31 of the bridge 30 is frangibly connected to the planar surface of the respective second portion 222 of the base 20 by means of a pre-established fracture line 310, which will be better described below.

The fracture line 310, visible in the details of FIG. 5A-5C,6 11A-11C, 12, 17A-17C, 18, 23A-23B, 24, 29A-29C, and 30, is substantially parallel to the planar surface (and/or to the bearing plane defined by the first portion 220 of the upper surface 22 and to the median plane M) and is placed at a third distance d3 from the lower surface 21.

In a first and preferred embodiment shown in FIGS. 1-6, the third distance d3 at which the fracture line 310 is placed is intermediate with respect to (comprised between) the first distance d1 and the second distance d2.

For example, the third distance d3 is closer to the second distance d2 than the first distance d1.

The third distance d3 is substantially equal to or slightly higher than the second distance d2.

In a second embodiment shown in FIGS. 7-12, the third distance d3 at which the fracture line 310 is placed is substantially equal to or slightly higher than the first distance d1.

In a third embodiment shown in FIGS. 13-18, the third distance d3 at which the fracture line 310 is placed is substantially higher than the first distance d1, although it is always less than the distance from the lower surface 21 in which the surface, in view, of the tiles P to be placed side by side is located (which can be levelled and spaced by the device 10 and which are resting with the laying surface thereof on the bearing plane defined by the base 20.

Each leg 31 of the bridge 30 is substantially slab-like and has a longitudinal axis (prevalent direction) orthogonal to the planar surface of the second portion 222 from which it derives.

Each leg 31 has a height (in a direction parallel to its longitudinal axis) greater than the thickness of the tiles P to be placed side by side, so that the crosspiece 32 of the bridge 30 is always at a level (distance from the lower surface 21) greater than the level of the surface, in view, of the tiles P to be placed side by side.

Each leg 31 has a predetermined width, whereby width is intended as the size parallel to the median plane M (which intersects both the legs 31 and the cross-piece 32 of the bridge 30), i.e. parallel to the flanking direction D of the legs 31, which is, for example, less than the width of the planar surface of the respective second portion 222.

For example, the width of the leg 31 can be increased, in particular, the width of the leg 31 is substantially equal (or slightly less) than half the (minimum) distance between the two legs 31, i.e. the distance between the two internal facing edges). In practice, each leg 31 (i.e. the edge thereof facing towards the other leg 31) has a (non-zero) distance from the connecting surface of the upper surface 22 of the base 20, i.e. a cavity is defined between each leg 31 and the connecting surface.

Each leg 31 has a variable thickness (for example in sections) along the longitudinal axis thereof.

Leg thickness 31 is intended as the size of the leg 31 in the direction orthogonal to the median plane M of the bridge 30 which intersects both the legs 31 and the crosspiece 32 of the bridge 30.

Each leg 31 comprises a central sector 311 axially interposed between the crosspiece 32 and the lower end of the leg 31, wherein the central sector 311 is provided with two sidewalls opposite each other with respect to the median plane M.

The sidewalls of the central sector 311 are the zone of the leg 31 which comes into contact with the side-by-side tiles P resting on the first portion 220 of the upper surface 22 of the base 20 defining their mutual distance in a direction orthogonal to the median plane M.

The distance between the sidewalls defines the width of the joint (interspace) between the tiles P.

For example, the thickness of each leg 31 at each sidewall is suitably calibrated, for example it is equal to 1 mm, 2 mm or multiples.

Each leg 31 then comprises a block 313 adapted to interconnect the central sector 311 with the planar surface of the respective second portion 222 of the base 20.

The block 313 has, for example, a thickness, i.e. a transverse section made with respect to a plane orthogonal to the median plane M, less than (or at worst equal to) the mutual distance between the two sidewalls of the central sector 311.

The block 313 has an upper end connected to the central sector 311 and a lower end, which coincides with the lower end of the leg 31 as a whole, connected directly to the planar surface of the respective second portion 222 of the base 20.

The fracture line 310 is defined at the block 313, for example in a zone proximal to the lower end of the same and/or intermediate between the lower end thereof (or coinciding therewith) and the upper end thereof (excluded).

The fracture line 310, as shown in detail in FIGS. 5A-5C, 6 11A-11C, 12, 17A-17C, 18, 23A-23B, 24, 29A-29C, and 30, comprises a longitudinal cut 3100 developing longitudinally with a longitudinal axis A parallel to the flanking direction D of the legs 31.

For example, the longitudinal cut 3100 of each leg 31 is aligned along the flanking direction D with the longitudinal cut 3100 of the other leg 31.

The longitudinal cut 3100 of each leg 31 extends for a predetermined section of the width (dimension parallel to the flanking direction D) of the respective leg 31, preferably for the entire width of the respective leg 31 (i.e. of the block 313 on which it is defined), i.e. with whole development.

Preferably, each longitudinal cut 3100 defines a zone having a reduced transverse section with respect to the transverse section (in any direction and in particular in the direction orthogonal to the median plane M) of the entire leg 31 and, in particular, of the block 313.

The longitudinal cut 3100 in practice defines a weakened zone of the respective leg on which the fracture of the bridge 30 preferentially develops with respect to the base 20.

The longitudinal axis A of the longitudinal cut 3100 is parallel to the planar surface of the respective second portion 222 and to the median plane M.

The longitudinal cut 3100 has a section that is transverse (i.e. with respect to a plane orthogonal to the flanking direction D, i.e. to the longitudinal axis A of the respective longitudinal cut 3100) having a concave shape, with concavity turned outwards (i.e. from the side opposite to the median plane M).

For example, the aforesaid transverse section is rounded according to a first radius of curvature R1.

In practice, the shape of the longitudinal cut is substantially semi-cylindrical or defines a dihedral (“V”-shaped) angle whose vertex is tuned towards the inside of the leg 31 and is open on the opposite side from the median plane M.

The first radius of curvature R1 is substantially comprised between 0.4 and 0.2 mm, preferably equal to 0.3 mm.

The cut depth of the longitudinal cut 3100 defined along the thickness of the block 313 is substantially comprised between 0.01 mm and 0.02 mm.

Each leg 31, i.e. each block 313, comprises a pair of identical longitudinal cuts 3100, symmetrically arranged with respect to the median plane M of the bridge 30 (and of the base 20) which contains the flanking direction D, i.e. the longitudinal axis A of the longitudinal cut 3100.

In practice, the weakened zone of the leg 31, on which the fracture of the bridge 30 preferentially develops, is defined at the plane joining the vertices of the rounded concave shape according to a first radius of curvature R1 defining the two longitudinal cuts.

In practice, the thickness of the weakened zone is equal to the thickness of the leg 31, preferably of the block 313, minus twice the cut thickness.

Advantageously, each longitudinal cut 3100 is then connected to the portion of the leg 31 (i.e. of the block 313) above it by means of a rounded connecting surface according to a second radius of curvature, opposite and greater than the first radius of curvature R1 (for example comprised between 0.3 mm and 0.5 mm, preferably equal to 0.4 mm).

Each fracture line 310 further comprises at least one trigger element 3101 of the fracture, which is localized in a predetermined trigger zone of the longitudinal cut 3100 along its longitudinal axis A.

The trigger element 3101 defines the trigger zone of the longitudinal cut having the minimum thickness of the entire leg 31, i.e. having a thickness less than the thickness of the weakened zone of the longitudinal cut 310 (outside the trigger zone itself).

This minimum thickness (localized at the trigger element 3101) can be comprised between the zero thickness (comprised) and the thickness of the weakened zone of the longitudinal cut 310 (not comprised).

Advantageously, the trigger element 3101 is localized close to at least one axial end of the longitudinal cut 3101.

Preferably, but not limited to, the trigger element 3101 is localized close to at least one axial end of the longitudinal cut 3101 at a predetermined non-zero distance therefrom, for example at a distance along the longitudinal axis A of the longitudinal cut 3100 comprised between the thickness of the weakened zone (of the longitudinal cut 3100) and the thickness of the central sector 311 (and/or of the block 313). In an embodiment shown in FIGS. 5A, 11A, 17A, 23B and 29A, each fracture line 310 comprises a single trigger element 3101 placed close to a single axial end of the respective longitudinal cut 3100, preferably the external axial end (distal from the other leg 31).

In a further embodiment shown in FIGS. 5B, 11B, 17B, 23A and 29B and 5C, 11C, 17C and 29C, each fracture line 310 comprises a pair of trigger elements 3101 separated from each other along the longitudinal axis A of the longitudinal cut 3100 and, for example, each placed close to a respective axial end of the longitudinal cut 3100, preferably at the aforesaid predetermined non-zero distance therefrom.

In a preferred embodiment shown in FIGS. 5A-5C,6 11A-11C, 12, 17A-17C, 18, 29A-29C, and 30, each trigger element 3101 comprises or consists of a hole 3101 passing from side-to-side for the entire thickness of the respective leg 31, i.e. of the relative block 313, wherein the through axis of the hole 3101 is transverse with respect to the longitudinal axis A of the longitudinal cut 3100.

In greater detail, the through axis of the hole 3101 is orthogonal to the median plane M of the base 20 and of the bridge 30 (which contains the longitudinal axis A of the longitudinal cut 3100).

The hole 3101 is for example with a constant circular section, i.e. it has a substantially cylindrical shape.

It is not excluded that this hole 3101 may have different shapes according to the needs.

For example, as illustrated in detail in FIGS. 5C, 11C, 17C and 29C, the hole 3101 is for example with a polygonal, preferably quadrangular (or rhomboidal), constant section, i.e. it has a substantially prismatic shape.

Preferably, the through axis of the hole 3101 incises/intersects the longitudinal cut 3100, i.e. the vertex thereof (or minimum section), in the aforesaid predetermined trigger zone, i.e. at the predetermined (non-zero) distance from the respective axial end of the longitudinal cut 3100.

When the trigger element 3101 is a through hole 3101, the same trigger element is such as to affect (intersect) both the longitudinal cuts 3100 of the same leg 31 in the same trigger zone.

In an alternative embodiment not shown, the hole 3101 could be a blind hole (or a blind indentation), i.e. a pair of opposite coaxial blind holes, i.e. provided with a single central axis that incises/intersects the longitudinal cut 3100, i.e. the vertex thereof (or minimum section), in the aforesaid predetermined trigger zone, or at the predetermined (non-zero) distance from the respective axial end of the longitudinal cut 3100.

In an embodiment shown in FIGS. 23A, 23B and 24, each trigger element 3101 comprises or consists of a transverse cut 3101 which incises/intersects the longitudinal cut 3100 in the aforesaid predetermined trigger zone, i.e. at the predetermined (zero or non-zero) distance from the respective axial end of the longitudinal cut 3100.

In particular, at least one trigger element 3101 of each leg 31 (in the example the one placed at the external axial end of the longitudinal cut 3100), in this embodiment, is formed by a pair of (identical) opposite transverse cuts 3101, symmetrically arranged with respect to the median plane M of the bridge 30 (and of the base 20) which contains the flanking direction D, i.e. the longitudinal axis A of the longitudinal cut 3100.

Each transverse cut 3101 has a substantially “V” shape, for example with a rounded vertex, which for example incises/intersects the longitudinal cut 3100, i.e. the vertex thereof (or minimum section), in the aforesaid predetermined trigger zone, i.e. at the predetermined (non-zero) distance from the respective axial end of the longitudinal cut 3100.

In particular, each transverse cut 3101 is defined by a dihedral angle whose vertex corner faces the inside of the leg 31 and is open on the opposite side with respect to the median plane M.

The vertex corner of the dihedral angle formed by each transverse cut 3101 develops longitudinally in a transverse direction, preferably orthogonal to the longitudinal axis A of the longitudinal cut 3100, i.e. it develops substantially orthogonal to the lower surface 21 of the base 20.

The vertices of the transverse cuts 3101 of each pair of transverse cuts 3101 which forms a trigger element 3101 are spaced by a (non-zero) distance less than the distance between the vertices of the longitudinal cuts 3100 of the same leg 31.

Furthermore, at least one trigger element 3101 of each leg 31 (in the example the one placed at the internal axial end of the longitudinal cut 3100), in this embodiment, is formed by a single degrading wall whose vertex (preferably orthogonal to the longitudinal axis A of the longitudinal cut 3100, i.e. it develops substantially orthogonal to the lower surface 21 of the base 20) is placed at the respective axial (internal) end of the longitudinal cut 3100, i.e. of the leg 31.

Returning then to the overall shape of the leg 31, the upper end of the block 313, i.e. the zone in which the block 313 connects to the central sector 311, is placed at a fourth distance d4 with respect to the lower surface 21 of the base 20, which fourth distance d4 is greater than the first distance d1.

In practice, the upper end of the block 313 protrudes above the level defined by the bearing plane of the first portion 220 of the upper surface 22 of the base 20. For example, the fourth distance d4 is substantially equal to the sum of the first distance d1 and the second distance d2.

The upper end of the block 313 is connected to the central sector 311 of the leg 31 by means of a rounded connecting surface according to a third radius of curvature, which is concordant and greater than the first radius of curvature R1 (for example equal to the second radius of curvature), and/or by “V” inclined walls.

The crosspiece 32, which as said extends longitudinally with longitudinal axis thereof parallel to the flanking direction D, comprises a transverse section (with respect to a plane orthogonal to the median plane M and orthogonal to this flanking direction D) defining a thicker zone in a zone proximal to the upper end of the legs 31 and with whole longitudinal development.

This thicker zone defines a reinforcing beam for the bridge 30.

This thicker zone is overhanging at the top with a thinner gripping portion and is connected to the legs 31 by means of inclined connecting surfaces.

The reinforcing beam, in the zone interposed between the legs 31, i.e. superimposed on the first portion 220 of the upper surface 22 of the base 20, ends up at the bottom with a shaped edge, for example a “V”-shaped.

The distance of the shaped edge from the first portion 220 of the upper surface 22 of the base 20 is (abundantly) greater than the thickness of the tiles P to be laid. Moreover, the crosspiece 32 might have a longitudinal development (length) less than the maximum distance of the legs 31, i.e. of the external and opposite surfaces of the same (see FIGS. 1-18), or have a longitudinal development equal to the aforesaid maximum distance of the legs 31 (see FIGS. 19-30).

Furthermore, the crosspiece 32 could have holes or lightening openings 320, for example through- or blind ones, defined above the reinforcing beam of the bridge 30.

The bridge 30, with its portal shape described above, and the base 20 joined thereto, delimit a through opening 40 which crosses the bridge 30 and the base 20 in a direction orthogonal to the median plane M of the same, i.e. in a crossing direction C orthogonal to the median plane M (i.e. orthogonal to the flanking direction D between the legs 31).

The through opening 40 is delimited perimetrically by the crosspiece 32 and the legs 31 of the bridge 30 and by the upper surface 22 of the base 20.

More in detail, the through opening 40 is delimited at the top by the shaped edge of the reinforcing beam of the crosspiece 32, below (almost totally) by the bearing plane of the first portion 220 of the upper surface 22 of the base (i.e. the zone of the same underlying the crosspiece 32) and laterally by the internal facing edges of the legs 31.

The through opening 40 overall has a substantially rectangular shape.

The device 10 further comprises a pressure wedge 50, separated from the base 20 and from the bridge 30 (see FIGS. 31 and 32).

The pressure wedge 50 is a right-angled wedge, for example it is provided with a lower flat surface 51 and adapted to be arranged, in use, parallel to the bearing plane of the first portion 220 of the upper surface 22 of the base 20 and an upper surface 52 inclined with respect to the lower surface 51 and provided with abutment elements, such as teeth 53 or knurls.

The pressure wedge 50 then comprises two parallel side walls.

The pressure wedge 50 has variable (and steadily growing) thickness along its longitudinal axis from one end towards the opposite end.

The pressure wedge 50 is configured so that it can be axially fitted with clearance through the through opening 40 defined between the base 20 and the bridge 30 of the device 10 along the crossing direction C (see FIG. 32) which is orthogonal to the aforesaid median plane M of the bridge 30 and of the base 20.

For example, the maximum height of the pressure wedge 50 (maximum distance between the lower surface thereof 51 and the upper surface 52 thereof) is less than the height of the through opening 40 defined by the distance between the cross-piece 32 (i.e. the shaped edge thereof) and the upper surface 22 of the base 20 (i.e. the bearing plane thereof).

The shaped edge of the crosspiece 32 is able to engage the teeth 53 substantially like a pop-up during the translation inside the through opening 40 along the crossing direction C.

The width of the pressure wedge 50 is substantially equal to (slightly less than) the distance between the two legs 31 (i.e. between the two facing edges thereof).

The pressure wedge 50 is adapted to be fitted inside the through opening 40 and to slide, with the lower surface 51 resting on the surfaces, in view, of the tiles P resting on the bearing plane defined by the upper surface 22 of the base 20, in such a way that the upper surface 52 of the pressure wedge 50 come into forced contact with the shaped edge of the crosspiece 32 and the same pressure wedge 50 is thus pressed against both tiles P, placed on opposite sides with respect to the bridge 30, due to the thrust of the same towards the base 20 and the levelling of the same.

In light of the above, the operation of the device 10 is as follows.

The device 10 allows the laying of tiles P according to different laying schemes as illustrated in FIGS. 33a -33 c.

For coating a surface with a plurality of tiles P, it is sufficient to spread a layer of adhesive over it and, subsequently, it is possible to lay the tiles P.

In practice, where the first tile is to be arranged, it is sufficient to position a first device 10, whose base 20 is intended, for example, to be placed under four corners of respective two/four tiles P.

Once the base 20 has been positioned, it is sufficient to position the two/four tiles P so that each of them has a portion of the lateral sidewall in contact respectively with a sidewall of one or both legs 31.

In this way, the equidistance between the two/four tiles P that surround the bridge 30 and are resting on the bearing plane of the base 20 is ensured.

When for example the tiles P have particularly large dimensions, then it is possible to position a device 10 also at a median zone of the lateral sidewall of the tile itself. In doing so, the tile P rests on one or more bearing planes of respective bases 20. Generally, the work is done by first laying a tile P and subsequently at a corner or a sidewall thereof, a base portion 20 of the device 10 is inserted thereunder.

In this circumstance, the inclined surfaces 225 and the elongated conformation in a direction orthogonal to the median plane M of the second portions 222 of the upper surface 22 (lowered with respect to the first portion 220) and, for example, the slots 23 play an important role in facilitating (jointly) the wedging of the base 20 below the laying surface of the tile P however allowing the adhesive not to be completely scraped away from the laying surface itself.

Once the various bases 20 have been positioned with their respective bridges 30 which stand above the surfaces in view of the side-by-side tiles P as described above, until the adhesive has still not completely solidified, it is proceeded with the insertion of the various pressure wedges 50 inside each through opening 40, which, by pressing on the surfaces in view of the tiles P, locally at the various (median or corner) points, allow the perfect levelling of the surfaces in view of the same tiles. Finally, when the adhesive has hardened and set, it is proceeded with breaking the long bridge 30, causing, for example by means of an impulsive force directed parallel to the median plane M, the fracture along the fracture line 310 and thus removing the same bridge 30 (single-use) and the pressure wedge 50 (reusable) so as to be able to fill the joints between the tiles P without the base 20 being visible on the finished surface and no part of the base 20 being interposed between the tiles themselves.

In practice, the fracture triggers in a controlled way starting from one of the trigger elements 3101 of each leg 31 and propagates along the longitudinal axis A of the longitudinal cut 3100 up to the opposite axial end of the same, for example where it joins the other possible trigger element 3101 (where present), which contributes to keeping the fracture guided along the longitudinal axis A of the longitudinal cut 3100 along the entire width of the respective leg 31.

The invention thus conceived is susceptible to several modifications and variations, all falling within the scope of the inventive concept.

Moreover, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims. 

1. A levelling spacer device for the laying of slab-shaped products for coating surfaces, comprising: at least one base having a lower surface and an opposite upper surface defining a bearing plane for two tiles placed side by side; a spacer bridge perimetrically delimiting a through opening adapted to be crossed by a pressure wedge along a crossing direction, wherein the bridge is provided with: two legs mutually placed side by side along a flanking direction orthogonal to the crossing direction and each protruding from a respective portion of the upper base surface, in an orthogonal direction with respect thereto; and a crosspiece, which joins the top of the two legs along the flanking direction; each leg of the bridge being frangibly connected to the respective base portion by means of a respective predetermined fracture line, wherein the fracture line comprises: a longitudinal cut developing for a predetermined section of the width of the respective leg with a longitudinal axis parallel to the flanking direction; and at least one trigger element of the fracture localized in a predetermined trigger zone of the longitudinal cut along the longitudinal axis thereof.
 2. A device according to claim 1, wherein the trigger element is localized close to at least one axial end of the longitudinal cut.
 3. A device according to claim 2, wherein the trigger element is placed at a predetermined non-zero distance from the proximal axial end of the longitudinal cut.
 4. A device according to claim 1, wherein the trigger element is a through hole in the thickness of the respective leg with transverse through axis with respect to the longitudinal axis of the longitudinal cut, which incises the longitudinal cut in the predetermined trigger zone.
 5. A device according to claim 4, wherein the through hole has a section transverse to the through axis surrounded by a closed perimeter.
 6. A device according to claim 5, wherein the closed perimeter is contained in the respective leg.
 7. A device according to claim 1, wherein the trigger element is a transverse cut, which incises the longitudinal cut in the predetermined trigger zone.
 8. A device according to claim 1, wherein the trigger element defines the trigger zone of the longitudinal cut having a minimum thickness of the entire leg smaller than the minimum section of the longitudinal cut outside the trigger zone.
 9. A device according to claim 1, wherein the longitudinal cut is placed at a predetermined distance from the lower surface of the base, which is such as to be arranged below the level of a surface, in view, of the tiles resting on the base with a support surface thereof opposite to the surface in view thereof.
 10. A device according to claim 9, wherein the predetermined distance of the longitudinal cut from the lower surface of the base is smaller than a distance between the upper surface and the lower surface of the base.
 11. A device according to claim 1, which comprises a pair of trigger elements, separated from each other along the longitudinal axis of the longitudinal cut.
 12. A device according to claim 11, wherein each trigger element of the pair of trigger elements is placed close to a respective axial end of the longitudinal cut.
 13. A device according to claim 12, wherein each trigger element of the pair of trigger elements is placed at a predetermined non-zero distance from the respective proximal axial end of the longitudinal cut. 